Method for making basis for a dental restoration

Abstract

A method for producing a ceramic material, subsequently including mixing ceramic material, such as oxidic ceramic material, which as a raw material essentially comprises aluminum oxide, zircon oxide and/or titanium oxide, and glass component; melting at least the glass component in the mixture by sintering, where the glass component infiltrates the ceramic material and absorbs raw material of the ceramic material through a reaction at the surface; and bringing the mixture into a shape, such as powder, which is suitable for further processing, such as additional sintering. Also, a basis for the crown, the crown in its entirety having layers of for instance porcelain applied to the basis, and methods for producing the basis and the crown through subsequent processing steps, to which the basis is preferably subjected on the same underground, for instance based on CAD/CAM techniques.

What is claimed is:  
     
       1. Method of producing a basis for a dental restoration to be applied at a place of use comprising: 
       (a) providing an underground with a shape corresponding to the place of use;  
       (b) providing a ceramic-based material, said ceramic-based material having a maximum density and surface, said ceramic-based material formed by mixing a ceramic material selected from the group of aluminum oxide, zirconium oxide, and titanium oxide, with a glass component to form a mixture;  
       (c) sintering said mixture of said ceramic material and said glass component whereby said glass component infiltrates said ceramic material and through a reaction at the surface of said ceramic material, acquires raw material of said ceramic material such that the glass is strengthened; and said ceramic material is sintered to a lower density than the maximum density thereof;  
       (d) grinding the sintered mixture into powder form;  
       (e) applying said powder onto said underground;  
       (f) further sintering said powder to provide a basis;  
       (g) machining the basis to the desired dimensions; and  
       (h) repeating steps (f) and (g).  
     
     
       2. Method according to  claim 1  wherein said sintering process of step (c) takes place in vacuum at a temperature of between approximately 750 and 1100° C. and during between approximately 1 and 12 minutes. 
     
     
       3. Method according to  claim 1 , wherein said sintering in step (f) takes place in vacuum at a temperature of between approximately 90 and 1500° C. during between approximately 2 and 12 minutes. 
     
     
       4. Method according to  claim 1 , wherein applying said powder onto said underground further includes: 
       spraying said powder using a carrier fluid onto said underground, and  
       isostatically pressing said powder.  
     
     
       5. Method according to  claim 1 , wherein said applying said powder material comprises pressing said powder onto the underground using a counterpart thereby forming a cavity having the desired shape of the basis between the underground and the counterpart. 
     
     
       6. Method according to  claim 5 , where the underground and the counterpart are aligned during said pressing by at least one fit pin and one fit hole. 
     
     
       7. Method according to  claim 1 , further comprising removing the underground after applying said powder thereon. 
     
     
       8. Method according to  claim 1 , where the temperature during the step (c) sintering process is between approximately 1100° C. and 1200° C. 
     
     
       9. Method according to  claim 1 , where the step (c) sintering process occurs for 24 hours. 
     
     
       10. Method according to  claim 1 , comprising addition to said powder of at least one material selected from the group of metal oxides and pigments, after grinding and prior to applying said powder onto the underground. 
     
     
       11. Method according to  claim 1 , wherein said glass component comprises: 55-75 wt.-% SiO 2 , 0.5-30 wt.-% Al 2 O 3 , 0.5-30 wt.-% K 3 O, 0.5-15 wt.-% Na 2 O and 0.5-30 wt.-% LiO 2 . 
     
     
       12. Method according to  claim 11 , wherein said glass component additionally comprises, in a lesser quantity than 5 wt.-% material, at least one of the compounds selected from the group of BaO, CaO, SrO, La 2 O 3 , Sb 2 O 3 , TiO 2 , F 2 , B 2 O 3 , ZnO, MgO and CeO 2 . 
     
     
       13. Method according to  claim 11 , comprising 
       melting the materials of said glass components to obtain glass; and  
       grinding said glass in order to obtain said glass component for mixing with said ceramic based materials.